/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/

    function joint (value) {
        return new Promise((resolve, reject) =>{
                setTimeout(() => {
                    resolve(value)
                }, 10); 
        })
    }
    joint('hello').then(value=>{
        return joint(value+'lagou')
    }).then(value=>{
        setTimeout(() => {
            
            console.log(value+'I ♥ U')
            
        }, 10); 
    })
